Your monthly MetroCard could skyrocket by 50 percent to a budget-busting $168 in 10 years, according to a new report.

The MTA raised subway and bus fares 8.4 percent in 2011 and in 2013 — and the Independent Budget Office did an analysis of how much fares would cost over the next decade if that trend continues.

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In 2023, a weekly MetroCard would cost $45 (up from the current $30), and a monthly card would shoot up to $168 (currently $112). The base fare, which is now $2.50, would increase to $3.75 by 2023.

The 50 percent increase vastly exceeds the rate of inflation, which is projected to be 2.7 percent annually over the next 10 years.

“These fares are too damned high!” griped Gene Russianoff, of the Straphangers Campaign. “These fare hikes will burn the riders, and discourage them from using mass transit. And it’s just not sustainable in the long run.”

He called for Albany to provide greater support for the MTA to protect straphangers from rising fares.

MTA spokesman Adam Lisberg said it’s impossible to predict the agency’s revenue and expenses in the coming years.

“This report is purely hypothetical,” he said. “It’s just way too early to say what’s going to be in 2015 and 2017. It’s simply saying this is what has happened in the past, and extrapolating forward, this is what could be in the future.”

He also noted that the MTA already has been saving money by cutting $800 million a year out of its operating expenses since 2009 — and is on track to eliminate $1.3 billion a year by 2017.

Lisberg said some costs are out of the agency’s control, such as pension and health-care contributions and fuel costs.

New York City Transit has to rely more heavily on fares to fund itself than any other system in the United States, according to the IBO report.

Fares fund 58 percent of New York City’s subway and buses, compared with 38 percent in Boston and 36 percent in Philadelphia.

Allen Cappelli, an MTA board member, said fare increases every other year would be too taxing on riders, and he wants city and state officials to figure out a way to spare straphangers.

“These biannual increases for riders and toll payers are onerous and unsustainable,” he said.

“The state and city need to develop a new plan that properly funds mass transit and the capital needs of transportation that relies less on the riders and drivers, who already pay the highest percentage in the United States.”

Office manager Nicola Heath, 23, said yesterday that the projected increases would be too much for her wallet.

“I’ll have to stop taking the train,” she said. “It is ridiculous.”

Akida Alexis, 31, a security manager who lives in Bushwick, Brooklyn, said he was already struggling with day-to-day expenses.